Gutenberg: Gutenberg conflicts with Starter Content widgets

[carolinan]

Describe the bug
When Gutenberg is installed, and a site is set to "fresh", error messages are shown in the customizer for widgets included in a theme's starter content.

The site with the starter content can not be published until the widgets are edited.
In my tests, changing the widget title or content removed the error.

I am not familiar with the any changes made for the "Widget blocks in the customizer", but perhaps it is related.
It does not seem to be theme dependent, I tested different themes that includes starter content.
I only tested with Gutenberg 7.7.0 so I am not sure when the problem was introduced.

Code relevant to widgets in starter content:
https://core.trac.wordpress.org/browser/trunk/src/wp-includes/theme.php#L2035

https://core.trac.wordpress.org/browser/trunk/src/wp-content/themes/twentytwenty/inc/starter-content.php#L23

To reproduce
Steps to reproduce the behavior:

1. Create a new WordPress site or reset an existing install
2. Activate Gutenberg
3. Activate a theme with starter content, for example Twenty Twenty or Twenty Seventeen.
4. Go to the Customizer.
5. Press Publish
6. See the error: _Unable to save due to 2 invalid settings._

Expected behavior
I expect the starter content to be saved without errors.

Screenshots

OS: Win10
Browser: Chrome Version 80.0.3987.132
Additional context

Please add the version of Gutenberg you are using in the description.
Version 7.7.0
WordPress Version 5.3.2

[annezazu]

Thank you for the excellent reproduction steps! This made it very easy for me to tackle this. I was able to replicate this following the steps outlined above using the following setup:

• TwentySeventeen theme
• WordPress: 5.4
• Gutenberg: 7.9.1
• Chrome 81.0.4044.122
  

[carolinan]

Confirmed that this is still an issue with Gutenberg version 8.1

[katiebethbrown]

Same issue on

TwentySeventeen theme
WordPress: 5.4.2
Gutenberg: 8.3.0

[zdenys]

I can still reproduce with:

Twenty Twenty Theme
WordPress 5.4.2
Gutenberg 8.5.1

[alshakero]

I'm investigating this.

[alshakero]

It seems to be a core issue. I've created a Trac ticket and sent a pull request with the fix.

[geekinthegirl]

I came across the same issue this morning, where the user was unable to delete widgets from their footer after their site was reset.

Theme: Twenty Twenty
WordPress: 5.4.2
Gutenberg: 8.7.0

[jartes]

Had a similar situation. Disabling Gutenberg and saving customizer settings made the trick. Now, with Gutenberg enabled again customizer settings are saving with no error.

Gutenberg 9.0.0.
Twenty Seventeen.
WordPress 5.5.1.

[mattwiebe]

I was trying to dig into a fix for this, but I haven't been able to replicate this on any combination of:

WP: 5.5.1
Gutenberg: 9.1.0; 9.0.0
Themes: Twenty Twenty; Twenty Seventeen
Themes: Twenty Twenty and Twenty Seventeen.

Are people changing any values in the Customizer before saving? Which ones? I have tried saving the Starter Content as-is and also editing some widgets and still can't produce an error.

[carolinan]

Tested on 5.6-beta3-49486 with and without Gutenberg 9.3.0. Twenty Twenty-One and some personal theme projects.
I am no longer able to reproduce this issue.

[annezazu]

@carolinan thanks for updating! @mattwiebe thanks for testing! I'm going to go ahead and close this out as a result since this no longer seems to be an active issue. Please re-open if that's not the case.